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A215871 Number of permutations of 0..floor((3*n-2)/2) on odd squares of an 3Xn array such that each row, column, diagonal and (downwards) antidiagonal of odd squares is increasing 0
1, 1, 1, 2, 4, 12, 29, 110, 290, 1274, 3532, 17136, 49100, 255816, 750325, 4124406, 12310294, 70549050, 213446666, 1264752060, 3868253164, 23555382240, 72686739116, 452806924752 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Row 3 of A215870

LINKS

Table of n, a(n) for n=1..24.

EXAMPLE

Some solutions for n=6

..x..0..x..2..x..3....x..0..x..2..x..4....x..0..x..1..x..4....x..0..x..1..x..4

..1..x..4..x..6..x....1..x..3..x..6..x....2..x..3..x..5..x....2..x..3..x..6..x

..x..5..x..7..x..8....x..5..x..7..x..8....x..6..x..7..x..8....x..5..x..7..x..8

CROSSREFS

Sequence in context: A148183 A148184 A148185 * A130135 A048618 A083554

Adjacent sequences:  A215868 A215869 A215870 * A215872 A215873 A215874

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 25 2012

STATUS

approved

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Last modified April 5 00:43 EDT 2020. Contains 333238 sequences. (Running on oeis4.)